1. Field of the Invention
The present invention relates to a device for monitoring a switching location for time-division multiplexing a combination of a plurality of communications channels for digital signals, particularly for pulse code modulated (PCN) signals, to form a common transmission channel in one transmission direction and for demultiplexing a common transmission channel into a plurality of communications channels in the opposite transmission direction, whereby the signals of the individual communications channels are combined to form pulse messages, each of which is preceeded by a frame recognition word which is monitored by a monitoring memory both with respect to its bit sequence and with respect to its periodicity.
2. Description of the Prior Art
Equipment of the type generally set forth above for combining a plurality of communications channels into a single transmission channel by way of multiplexers and for the corresponding execution of the opposite switching events (demultiplexing) are frequently established in unmanned offices and at great distance from maintenance stations since a high degree of reliability of operation is generally guaranteed due to the utilization of integrated components. However, precisely because of the anticipated reliability, the necessity is established of creating quick evaluation in the case of a malfunction. This requires that the nature of the respective malfunction be rapidly perceived in order to be able to quickly replace the malfunctioning components and eliminate the malfunction.
Various measures have already become known in the art for malfunction recognition. In a switching location of the aforementioned type, which is usually under supervision of personnel having little training, what is involved is that all possible errors be easily perceived and capable of being easily eliminated.